View Full Version : Plenums

20-01-2005, 08:12 PM
When installing a ceiling concealed AC type with isolated flexible ducts, do you always use the standard plenums (sheetmetal) to blow the air through the grille?
are these sheetmetal plenums isolated to prevent condensation?
Are some of you making these themselves?

Here are some pictures how we do it.
The first serie of photos is plenums made with 4 different 6 different pieces, glued together in the corners. After making the corners, (how do youi say it, using glue... glueing?) we then seal the corners with alu tape.

20-01-2005, 08:18 PM
These are those we cut in a 90 corner, just not through the outside.
We then bend them over 6 times (also the end plates are then in 1 piece) and the outside is then very smooth, we don't have to use alu tape for it.
Picture 3 is the PU foam coming out of the corners which can be broken of.

20-01-2005, 08:20 PM
1 stpicture just bended over without glue.
Then the connection for the flexible hose.
Make a hole, put the ring in it and then bend over the small pieces.
There has to be kit or glue between the connection and the case.

20-01-2005, 08:25 PM
We buy them in, rather inexpensively.

What is the cost for this plenum Marc?
Estimate price for a plenum for a line grill of +/- 5 ft long ,10 inch heigh, 10 inch width.

20-01-2005, 08:45 PM
That's the price for the plenum as can be seen in the picture you posted? Isolated?
We can make it for +/- 60 to 70 Euro or 40 . (Rough estimate)

20-01-2005, 08:45 PM
I don't like the flexible insulated ducts.

Plenums are real cheap here, made of plastic, almost unlimited combinations of flexible hoses, they also come with a metal mesh for even air flow.

I still Prefer the insulated metal sheet ducts.

Chemi :)

20-01-2005, 08:49 PM
It's a common practice here.
Why don't you like them Chemi?
It's going fast, they're isolated, if proper sized almost no noise, rather cheap,....
Can you mail an adress of a manufacturer or wholesaler of th plastic ducts.
What about isolation, static voltage on the plastic tubes, ...
How can the mesh make an even airflow? We use for this constant volume regulators.

20-01-2005, 09:17 PM
Here soem of us make it themselves , the others buy it , it coasts about 40 USD + 10% VAT , as for flexible insulated duct , it's widely used ... quick install and low price

20-01-2005, 09:35 PM
..t coasts about 40 USD + 10% VAT , as for flexible insulated duct , it's widely used ... quick install and low price
40 $ for what Botrous? Sheetmetal ducts? and +/- what dimensions.

20-01-2005, 10:18 PM
I wonder if i can sell these to the company i'm working for at the moment?
No Skillcard needed to knock these up.



20-01-2005, 11:18 PM
The return plenum's .....
Have I caught him at last or will debate begin ? :)
I was always taught that only the 'supply' can be a plenum because it is an space under pressure not a vacuum.

Now I know that in the strictest sense a return air duct is not under a vacuum as we normally refer to it. However the only way that the air can 'return' to the fan on the inlet side is to be below the surrounding atmospheric pressure; does that classify it as being 'not under pressure' ?

21-01-2005, 12:38 AM
Estimated price for a plenum for a line grill of +/- 5 ft long ,10 inch heigh, 10 inch width in lebanon is 40 USD + 10% VAT Peter , that's what i'm talking about

21-01-2005, 01:01 PM
<snip> my use of the word "plenum" would still be correct by concept....
Damn :mad: :mad: :D

22-01-2005, 07:20 AM
Hi Peter.

I guess I'm old fasioned about ducts.
I wil try to remember to take my Sony and post a few pictures of this plastic plenum and the mash.

Feel free to remind me ;)

Chemi :)